The field of the present invention is lubricated gearing; and more specifically lubricated gearing particularly adaptable to vehicle transmissions.
Gearing associated with vehicles and particularly exposed transmissions for motorcycles and the like can produce significant, objectionable noise. Gear noise resulting from the individual contact of gear teeth is often present due to backlash in the gears. Such noise may result from torque fluctuation to the drive gear. The gear teeth impacting noise may be reduced by reducing backlash. However, in doing so, a buzzing noise may be induced which is caused by the rubbing of the faces of the gear teeth. The remedies for the two sources of noise, gear tooth impacting and buzzing, are counterproductive. This condition makes it extremely difficult to minimize both noises.
In addressing the foregoing problem, two current solutions are illustrated in FIGS. 1 and 2. Looking first to FIG. 1, a driven gear is illustrated as being composed of two gear wheels which are arranged in juxtaposition to rotate together. One of the two wheels is angularly biased by a spring or the like such that the teeth are slightly angularly misaligned. This enables the driven gear to exert resilient pressure against the drive gear to reduce backlash noise without as much buzzing noise as might otherwise occur.
FIG. 2 illustrates another driven gear composed of two gear wheels. The two gear wheels are brought together with an angular friction force therebetween. The smaller of the two gear wheels has one less tooth than the larger, power transmission wheel. The friction force between the gears causes the exta gear to drag on the power transmission gear so as to cause positive meshing with the drive gear. As with the device of FIG. 1, backlash noise may be mechanically controlled. However, optimum buzzing noise is not achieved. As a result, neither solution is totally satisfactory. With substantial drive torque fluctuation in either system, an increased force between the two gears is necessary, spring force for the device of FIG. 1 and friction force for the device of FIG. 2. However, in increasing the relative force between gear wheels, a greater tendency to produce buzzing exists.
Naturally, lubricant has a tendency to reduce gear noise. However, conventional lubrication in power transmissions, particularly for motorcycles, employs the splashing of lubricant from one of the gears, see FIG. 3. The results are sufficient for lubrication but do not provide sufficient amounts of lubricant for noise reduction.